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Skookum Robotics Skookum Robotics SK-360 SK-540 & SK-720 Digital Flybar


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Old 01-25-2009, 05:01 PM   #1
rcmike
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Default Pitch throw problem

Hey guys, I have been flying my Trex 600N with the SK360 for a little while but I noticed today after getting a wixey angle gauge that I am not getting as much negative pitch as positive. While fiddling with it I noticed that the servos stop moving before the stick gets to the bottom. I am using a Futaba 9C with spectrum module and an AR7100R. The throttle moves throughout the stick movement and I plugged a servo directly into the pitch channel on the receiver and it moves throughout the stick range so it has to be something in the SK360. I have the mixing done in the SK360 as well. Am I overlooking something obvious in the programming?
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Old 01-26-2009, 05:31 AM   #2
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Yes i had the same problem using a futaba 7c it seems that with futaba there is this problem.

What you need to do is alter the end points on your tx channel 6 until the readout on the 'inputs from receiver' 'pitch' panel in the setup software reads as near to 100 both ends

on my 7c this is 78 up and 70 down, seems a shame to lose that resolution but i think its the only way.
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Old 01-26-2009, 06:03 AM   #3
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Can't you fix the loss of resolution by increasing your endpoints? It should be possible to use your transmitters full resolution as opposed to only half. That's one of the reasons for going flybarless for me: increased resolution on your swashplate.
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Old 01-26-2009, 06:26 AM   #4
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Thanks guys, I'll give it a try and see what I can do when I get home from work.
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Old 01-26-2009, 10:38 AM   #5
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Quote:
Originally Posted by rcmike View Post
Thanks guys, I'll give it a try and see what I can do when I get home from work.
Increasing the endpoints will make rcmikes problem worse not better
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Old 01-26-2009, 11:03 AM   #6
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So beyond a certain point the skookum does not see an increase in stick deflection?! Meaning that increasing the endpoints will actually make the skookum stop reacting even closer to midstick?

That sounds like a 'must fix' for the next firmware
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Old 01-26-2009, 11:08 AM   #7
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Exactly. Once the stick gets to a certain point it just quits. I decreased the endpoints and it works now but it is irritating to go through all the head mods to get more resolution and then have to reduce it in the TX. Skookum, if you are watching, will a firmware update be able to fix this? Is it only a problem with Futaba radios?
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Old 01-26-2009, 03:19 PM   #8
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I have small issues with this , with my dx7

its crappy cheap ass "pots" in my radio .and nothing to do with the SK . but my radio has been hammered for 3 years of 3d . stick banging ...

going from full stick to min gets random results like 0,1,3,2,0 at min , and 99,100,96,97
in the TX input section

if i repeatedly push full pitch , then min, then full pitch again , or ele ,aile .... its not a big deal , but makes me want to test a new DX7 on my SK in the shop , BEFORE i TAKE IT from the shop ie another new DX7

I like the fact that the sk shows up the faults in my radio pots , and kind of reflects the cheap price of my Dx radio , its NOT a 14mz !!!


how old is the radio ? i was thinking of setting my radio end points to get a true '100' up and a true ' 0' down in my sk setup .... but havent as my SK flys that good , i have a serious fear of changing anything about it ...


SO, Art is this tolerable to the unit .??... FINE trimming radio endpoints ( NOT pushing 150 each way , like 103 , or 104) to get perfect throws in the SK setup /? for the TX INPUTS not the overall setup as such

awaiting a reply
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Old 01-26-2009, 04:48 PM   #9
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The radio is about 2 years old but I really haven't used it much until the last few months. It shouldn't in any way be worn out. After setting up the pitch to where the total throws are the same I measure pitch at each white mark on the gimbal and the the positive and negative readings are identical so I am pretty sure the gimbal is working as it should.
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Old 01-26-2009, 05:42 PM   #10
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what head conversion are we talking ??

jase
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Old 01-26-2009, 05:53 PM   #11
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http://www.helifreak.com/showthread....ght=flybarless
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Old 01-26-2009, 06:06 PM   #12
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ok , looking at your head , it definately would be the case that you would have equal throws ..


hmm, are your servos 50/50 servos , or are the 60/40 or are they 70/30 in throw by design ... that could lead to issues as well. if you are mixing them to get 50/50


i use a modified 500 head on my 500 and as a result it gets more initial +ve pitch then initial -ve pitch in flight ,, i ended up having to drop point 2 on my pitch curve back to 20 from 25 , to get the -ve pitch to feel right in flight ..
i am not sure ... i did have to fiddle alot with my head set-up to get the full + and - pitch to match perfect with zero pitch at zero stick also ..

but i had to do that on the standard non flybarless head also ... all my arms are equal in length and 90 in set-up .??

i put it down to my s9650 servos being inaccurate .

but still run slightly kinked pitch curve to get it to feel right in actual flight . and its fly's great on all points , my pitch curve is 0,20,50,75,100 + - 15 deg collective .

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Old 01-26-2009, 07:14 PM   #13
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The problem is there is no servo movement past a certain point unless the endpoints are reduced. The servos are nowhere near the end of their throws and it doesn't matter what value the collective pitch is in the swash mixing menu.
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Old 01-26-2009, 09:06 PM   #14
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Quote:
Originally Posted by rcmike View Post
no servo movement past a certain point unless the endpoints are reduced.

That is not logical ...did you mean , no servo movement past a certain point unless the endpoints are increased ??

have you got your travels in the servo tab in set-up software at 150 % ??both ways ??,

if you have the servo tab maxed out (150,150..150,150..150,150 ) , swash mix at 60 (recommended) and still not enough throw then the geometry is out ,. ie

the grip spacing is two wide.
or
the servo horn is to short on the collective servos .

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Old 01-26-2009, 09:17 PM   #15
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That was how I meant it but let me clarify. I have to decrease the endpoints in the TX, not the SK, to get it to work. I have the endpoints in the SK set to 125. I can get rediculous amounts of throw but the problem is that there is no servo movement at the bottom of the stick no matter how it is adjusted unless I decrease the endpoints in the TX. Even when there is no movement at bottom stick I can give cyclic and it will go further so the amount of throw I can get isn't the problem.
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Old 01-26-2009, 09:44 PM   #16
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is your pitch curve 0-100 ? in normal, HOLD!, st1,st2,st3??

if its got less pitch in the curve it wont go any lower. ie if your curve was 30,30,50,75,100

im not understanding why reducing TX throw would increase throws on servos in set-up or flight mode.

its set at 100 % and forget.


tune from the SK , i did have to reverse my pitch channel on my radio to get +ve pitch and a green light in setup
the sk will give you a range to work with , you do need to set-up a head within that range .. ???

i get a pitch range of 30 degress collective with my servo tab at 140 all 3 servos , and swash mix at 60 , absolutely ship loads

trying to help ......really ..... shoot a video , up on youtube . just 30 seconds to show us all what you are trying to say
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Old 01-27-2009, 04:47 AM   #17
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on my and others futaba radio if the pitch end points are at 100 then on the sk software the 'input from receiver' 'pitch' panel the figure goes from -140 to 140 instead of -100 to 100. if you leave this as it is then when the figure reachs 100 the movement of the servos stops and the pitch stick has a dead area at each end of its throw. The only way i have found of dealing with this is to either lower the endpoints in the radio or change the pitch curveto something like 20 30 50 60 80 .
have a look here
http://www.helifreak.com/showthread.php?t=100830
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Old 01-27-2009, 06:02 AM   #18
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Exactly! That is what I have been trying to explain. Thanks SE.
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Old 01-27-2009, 06:13 AM   #19
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that should be noted in the manual , , now it all makes sence ..

thanks for being an interpreter for me and rcmike Mr skint


are airtronics and sanwa radios like this .... i only use 2.4 gig gear these days , so an guilty of being tunnel visioned... other than the 14mz do futaba still sell a radio ??? LMAO


so problem solved ... woo hoo !! thank god that wasnt making much sence , so the futaba radio is not ment for flybaless systems .. ??

lol just kidding ,,,, ok rc mike , go fly !!
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Old 01-27-2009, 06:18 AM   #20
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Yeah, I knew what I wanted to say but for some reason I couldn't put it into words others could understand.
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